Spectral analysis system for capturing a spectrum

ABSTRACT

Spectral analysis system for capturing a spectrum including an inlet opening, a dispersive optical element and reflecting imaging optics having at least one optical functional element defining an optical path from the inlet opening across the dispersive optical element onto an outlet opening and/or detector area of the spectral analysis system and a carrier member defining a flat optical path volume with at least one lateral opening. The dispersive optical element is configured, e.g. in a stationary manner. At least one of the inlet opening, the outlet opening and/or detector area, the at least one optical functional element and the dispersive optical element are integrated in at least one member. The at least one member is mounted on the carrier member at the at least one lateral opening, such that the optical path largely runs transversely to a thickness direction of the optical path volume.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No. 102018 205 401.0, which was filed on Apr. 10, 2018, and is incorporatedherein in its entirety by reference.

Embodiments according to the invention relate to a spectral analysissystem for capturing a spectrum of electromagnetic radiation.

BACKGROUND OF THE INVENTION

In spectroscopy, so-called spectroscopic apparatuses are frequently usedfor detecting/measuring the spectrum of electromagnetic radiation, inparticular in the spectral ranges ultraviolet (UV), visible (VIS) andinfrared (IR). Here, the dispersive element needed for splitting theelectromagnetic radiation is frequently configured as diffractiongrating. New applications where spectroanalytical measurements play animportant part, such as environmental measurement technology and foodanalysis need small, robust and cost-effective spectroscopicapparatuses, possibly in very large quantities. Here, it has to beconsidered that some of these applications call for powerful devices,comparable to commercially available compact spectrometers. As oneexample, the spectral resolution of such devices of 10 nm half width inthe near infrared spectral range of 1000 nm to 1900 nm is stated.

The above-stated requirements cannot all be fulfilled at the same timewith conventional technology. The three issues small structural size,low cost and large quantities at least partially contradict each other.With constant device performance, miniaturization results in complexcomponents and/or assembly processes. This increasing complexity againcauses increased production costs which may have a negative effect onthe production of very large quantities. Solutions that can be producedat low cost in large quantities do not reach the requested performance.

MEMS-based spectrometers are known from conventional technology. MEMSspectrometers mean embodiments that are provided with a movablediffraction grating. These devices are produced in respectivemicrotechnology and have an integrated drive for deflecting a gratingmirror plate. With the selection of a suitable material system, e.g.,silicon and the matching drive type, e.g., electrostatic, deflectablediffraction gratings having a large deflection amplitude can beproduced, which are particularly well suited for the design ofminiaturized spectroscopic apparatuses. A detailed description of suchsystems can be found in U.S. Pat. No. 8,045,159 B2 about hybridspectrometers.

Laboratory and compact spectrometers are already known. These are, amongothers, Czerny-Turner spectrometers/spectrographs as standard andcrossed variation. Further, MEMS grating spectrometers in stacked designwith complex optical members are known which can, among others, beproduced in a miniaturized manner.

For miniaturized and precise spectrometers, very small inlet openingsand outlet openings might be needed. MEMS gaps in different substrateconfigurations are known.

In view of the above, there is a need for a concept allowing an improvedtradeoff between reducing the structural size, reducing the cost as wellas producing spectroscopic apparatuses in large quantities. Thus, aminiaturized spectroscopic apparatus comprising, for example, all theabove-stated features is to be provided.

SUMMARY

According to an embodiment, a spectral analysis system for capturing aspectrum may have: an inlet opening, a dispersive optical element and anat least partly reflective imaging or beam forming optics including atleast one optical functional element defining an optical path from theinlet opening across the dispersive optical element onto an outletopening and/or detector area of the spectral analysis system, whereinthe dispersive optical element is configured in a stationary manner; anda carrier member defining a flat optical path volume having at least onelateral opening, wherein at least one of the inlet opening, the outletopening and/or detector area, the at least one optical functionalelement and the dispersive optical element is integrated in at least onemember, wherein the at least one member is mounted on the carrier memberat the at least one lateral opening, such that the optical path mainlyruns transversely to a thickness direction of the optical path volume.

Another embodiment may have a method for capturing a spectrum by meansof an inventive spectral analysis system.

One embodiment relates to a spectral analysis system, herein alsobriefly referred to as spectrometer for capturing a spectrum. Thespectrometer includes an inlet opening, a dispersive optical element andan at least partly reflective imaging or beamforming optics having atleast one optical functional element defining an optical path from theinlet opening across the dispersive optical element to an outlet openingand/or detector area of the spectrometer and a carrier member defining aflat optical path volume having at least one lateral opening. Here, theat least one lateral opening does not have to be an opening completelypenetrating the carrier member but can also be, for example, a blindhole or a sink hole being at least open towards the optical path volume.Here, the optical path volume is defined, for example, such that a firstplane of the optical path volume to which the dispersive optical elementand the reflective imaging optics are perpendicular or almostperpendicular has a greater expansion than a second plane oriented inparallel to the dispersive optical element and the reflective imagingoptics and perpendicular or almost perpendicular to the first plane. Inother words, the optical path volume has a thickness direction (along az axis) forming a or being perpendicular to the first plane (expansionin xy direction), wherein the optical path volume has, in thicknessdirection, a smaller expansion than an expansion within the first plane(e.g., an expansion in x or y direction or an expansion of the size ofthe clear dimension of the first plane). Additionally, in thespectrometer, at least one of the inlet opening, the outlet openingand/or detector area, the at least one optical functional element andthe dispersive optical element integrated in at last one member. Thedispersive optical element is configured, e.g. in a stationary manner.The at least one member is mounted to the carrier member at the at leastone lateral opening, such that the optical path runs mostly transverselyto the thickness direction, i.e., mainly laterally. For example, morethan 50% of the distance of the optical path runs at an angle between70° and 110°, 80° and 100° or 85° and 95°, each inclusive, relative tothe thickness direction, such as at an angle of 90°, wherein more than75% is also possible. In other words, the projected optical pathtransverse to the thickness direction has an angle between main sectionnormal of the optical path transversal to the thickness direction andthickness direction between 0° and 20° or between 0° and 10° or 0° and5°. The ratio of the optical path not transversal/transversal to thethickness direction is, e.g. at least 0 (no deflection mirrors) and atmost 1:1,3 or 1:1,2 or 1:1,1. The at least one opening is, for example,an opening completely penetrating the carrier member. Then, the at leastone member is mounted, for example, to the carrier member from theoutside, i.e., to a side of the carrier member facing away from theoptical path volume or the outside. However, the opening may not only beopen towards the optical path volume but also transversal to the same,such as towards the top or bottom in the figures. Then, the at least onemember could be inserted from there into the opening and mounted in theopening, i.e., along the thickness direction. Additionally, it ispossible that the opening is not configured as passage opening but formsa funnel or a cavity, such as a blind hole that is opened towards theoptical path volume and optionally also transversal to the same and intowhich the at least one member is inserted. Inserting is performed, forexample, by means of a robot or “pick-and-place” method. This allows acompact design with the additional option of using spherical optics andhence lower production costs. Projected along a thickness direction ofthe optical path volume, the optical path can additionally be configuredsuch that the same has crossing optical path portions. Thereby, an evenmore compact design becomes possible.

Embodiments of the spectrometer are based on a knowledge that individualelements (e.g., the inlet opening, the outlet opening and/or detectorarea, the at least one optical functional element and the dispersiveoptical element) or members of the spectrometer at a carrier can beeasily and quickly disposed on a carrier member, for example by apick-and-place method, whereby production of the spectrometer in largequantities becomes possible. Additionally, the individual elements andmembers can be produced quickly, simply and inexpensively by methodssuch as injection molding, glass molding, laser production, etc.

In one embodiment, the carrier member defines a flat optical path volumehaving at least two lateral openings. The at least two lateral openingscan be at an angle to each other without causing any significantproblems. The carrier member can be produced, for example, in injectionmolding, i.e., the same can be an injection molding member and canrealize, in particular, all orientations of the at least two membersthat are advantageous for a compact design. In that way, thespectrometer can e.g., comprise two members, wherein, e.g., an opticalfunctional element, such as a concave mirror is integrated in a firstmember and a further optical functional element, such as concave mirroror the dispersive optical element as well as optionally the outletopening and/or the detector surface is integrated in a second member. Inthe latter case, the dispersive optical element as well as the outletopening and/or the detector area could be arranged in the second memberadjacent to one each other such that, when the second member is disposedat one of the at least two lateral openings, the same point in thedirection of the optical path volume. Even when in this example twoelements (two of the inlet opening, the outlet opening and/or detectorarea, the at least one optical functional element and the dispersiveoptical element) are integrated in one member, the spectrometer can alsoonly comprise members into which only one element (e.g., the inletopening, the outlet opening and/or detector area, the at least oneoptical functional element and the dispersive optical element) each ormore than two elements is/are integrated.

Further, the at least two lateral openings of the carrier member can beoriented freely. The same can, as mentioned, be disposed at an angle toeach other, such as at an angle to each other about an axis parallel tothe thickness direction, wherein the orientation can be selected forminimizing the needed optical path volume. Additionally, it is easilypossible to form a crossing optical path, whereby the optical pathvolume can be reduced further. By this freely orientable, possibly“skew” design, combined with an optionally crossing optical path, thespectrometer can be realized very in a very small manner with littleproduction effort.

Thus, it has to be stated that elements and members of the spectrometerare configured or arranged such that production of the spectrometer inlarge quantities and/or as a very small system while reducing the costsis enabled.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be detailed subsequentlyreferring to the appended drawings, in which:

FIG. 1 is a schematic illustration of a spectrometer according to anembodiment of the present invention;

FIG. 2a is a schematic illustration of a spectrometer having two opticalfunctional elements according to an embodiment of the present invention;

FIG. 2b is a schematic illustration of a spectrometer having a foldedoptical path and a fixed dispersive optical element according to anembodiment of the present invention;

FIG. 2c is a schematic illustration of a spectrometer having a crossedoptical path and a fixed dispersive optical element according to anembodiment of the present invention;

FIG. 2d is a schematic illustration of a spectrometer having a crossedoptical path and a fixed dispersive optical element according to analternative embodiment of the present invention;

FIG. 3 is a schematic illustration of a dispersive optical element forthe spectrometer according to an embodiment of the present invention;

FIG. 4 is a schematic illustration of an MEMS gap for the spectrometerproduced with silicon microtechnology according to an embodiment of thepresent invention;

FIG. 5 is a schematic illustration of a gap for the spectrometerproduced in metal by means of laser material machining according to anembodiment of the present invention;

FIG. 6 is a schematic illustration of a member of the spectrometeraccording to an embodiment of the present invention;

FIG. 7 is a schematic illustration of a member of the spectrometer intowhich both an outlet gap as well as a dispersive element are integrated,according to an embodiment of the present invention;

FIG. 8 is a schematic illustration of two members of the spectrometerthat are arranged on top of one another according to an embodiment ofthe present invention;

FIG. 9 is a schematic illustration of three members of the spectrometerthat are arranged above one another according to an embodiment of thepresent invention;

FIG. 10 a schematic illustration of the spectrometer withoutillustration of the carrier member according to an embodiment of thepresent invention;

FIG. 11 is a schematic illustration of the course of the optical path ofthe spectrometer according to an embodiment of the present invention;

FIG. 12 is a schematic illustration of the spectrometer including threedeflection mirrors according to an embodiment of the present invention;

FIG. 13 is a schematic illustration of a bottom of the spectrometer ofFIG. 12 according to an embodiment of the present invention;

FIG. 14 is a schematic illustration of a lid of the spectrometer of FIG.12 according to an embodiment of the present invention;

FIG. 15 is a schematic illustration of a lid of the spectrometer of FIG.12 without the inlet gap and without the outlet gap according to anembodiment of the present invention;

FIG. 16 is a schematic illustration of a lid of the spectrometer of FIG.12 with deflection mirrors according to an embodiment of the presentinvention;

FIG. 17 is a schematic illustration of the spectrometer including twodeflection mirrors according to an embodiment of the present invention;

FIG. 18 is a schematic illustration of a bottom of the spectrometer ofFIG. 17 according to an embodiment of the present invention;

FIG. 19 is a schematic illustration of a lid of the spectrometer of FIG.17 with a substrate according to an embodiment of the present invention;

FIG. 20 is a schematic illustration of a lid of the spectrometer of FIG.17 with a substrate and two deflection mirrors according to anembodiment of the present invention;

FIG. 21 is a schematic illustration of the spectrometer having only oneoptical functional element according to an embodiment of the presentinvention; and

FIG. 22 is a schematic illustration of the spectrometer of FIG. 21having only one optical functional element and no crossed optical pathaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Before embodiments of the present invention will be discussed in detailbased on the figures, it should be noted that identical, functionallyequal or equal elements, objects and/or structures in the differentfigures are provided with the same reference numbers, such that thedescription of these elements illustrated in different embodiments isinter-exchangeable or inter-applicable.

FIG. 1 shows a schematic illustration of a spectral analysis system 100,here also briefly referred to as a spectrometer 100 for capturing aspectrum according to an embodiment of the present invention. Thespectrometer includes an inlet opening 110, a dispersive optical element120 and a reflective imaging optic 130 having at least one opticalfunctional element 132 defining a crossing optical path 142 from theinlet opening 110 across the dispersive optical element 120 to an outletopening and/or a detector area 150 of the spectrometer 100 and a carriermember 160 defining a flat optical path volume 140 having at least onelateral opening. In FIG. 1, for example, four openings are shown. Oneopening corresponds to the inlet opening 110, the outlet opening and/orthe detector area 150 is disposed at a further opening, the reflectiveimaging optics 130 is disposed at a third opening and the dispersiveoptical element 120 is disposed at a fourth opening. In the spectrometer100, at least two of the inlet opening 110, the outlet opening and/orthe detector surface 150, the at least one optical functional element132 and the dispersive optical element 120 are integrated in at leasttwo members. In that way, for example, the reflective imaging optics 130is integrated in a first member and the dispersive optical element 120in a second member. In other words, the reflective imaging optics 130forms a first member and the dispersive optical element 120 forms asecond member. The two members are mounted on the carrier member 160 attwo of the four lateral openings, such that the optical path 140,projected along a thickness direction (z axis perpendicular to the paperplane) of the optical path volume 140 comprises crossing optical pathportions. The at least two lateral openings are at an angle to eachother. This means that the two openings are, for example, not parallelor perpendicular to one another.

The carrier member 160 can be a single member, e.g., from one mold. Inthat way, FIG. 1 shows, for example, a top view and the individualshaded elements of the carrier member are connected to one another, forexample, via a bottom plate. The bottom plate limits, for example, theoptical path volume on one side and can be perpendicular to thethickness direction. The elements of the carrier member 160 illustratedin a shaded manner can represent lateral walls that are connected toeach other via the bottom (bottom plate) not illustrated in FIG. 1. Theat least one lateral opening is disposed in at least one of the lateralwalls. The expansion of the optical path volume 140 in thicknessdirection is, e.g., in a range of 3 mm to 30 mm, 3 mm to 20 mm, 3 mm to10 mm or 3 mm to 5 mm, such as 4.5 mm.

According to an embodiment, the carrier member 160 can represent amolded body produced, e.g. by means of injection molding, 3D printing,metal investment casting, metal centrifugal casting or metal diecasting. Here, the carrier member can be produced, e.g., as half-shellmodel. In that way, a very fast and precise production of the carriermember 160 suitable for mass-production is obtained, e.g. withoutadditional steps for realizing the at least one opening. Half-shellmodels allow precise production and assembly since, e.g. between thehalf-shells, gaps can be realized for adjusting the half-shells withrespect to one another and the members at openings of the carrier member160. A further advantage of realizing the carrier member 160 by means ofhalf-shell models is that the two half-shell models can comprisedifferent materials and can hence also have different functionalcharacteristics. According to an embodiment, the carrier member 160 canbe produced by means of two-component injection molding, wherein, e.g.,two different plastic materials, two different metal materials or aplastic material and a metal material are used.

According to an embodiment, the carrier member 160 can comprise, as amaterial, a metal material, such as an NF metal material(NF=non-ferrite) such as zinc, aluminium, magnesium, zinc alloy,magnesium alloy or aluminium alloy or plastic material. Metal materialis particularly advantageous since it screens the optical path volume140 from stray radiation from outside. According to an embodiment, dyescan be added in plastic materials, or surface modifications, such assurface coating or surface roughening can be performed in order toscreen stray radiation from outside and/or to realize a stray radiationabsorbing carrier member 160. Surface modifications can also beperformed in a carrier member comprising metal material for reducingstray radiation within the spectrometer. Due to the fact that thecarrier member 160 comprises, e.g., stray radiation absorbing material,influences by stray radiation can be minimized.

In one embodiment, the inlet opening and the outlet opening can beintegrated in a common member or can be disposed on the same.

In one embodiment, the carrier member 160 has an aspect ratio lateraldimension/thickness of typically 1.5 or 2.5 or 3.5 or 5, at least 1.25.Absolute values for dimensions of the carrier member 160 can, forexample, be less than 20×20×10 mm³, 10×10×6 mm³, 12×8×5 mm³, 8×8×6 mm³,10×10×5 mm³ or 8×6×4 mm³. These values are exemplary, they representdifferent applications and embodiments (focal widths, resolutions,etc.). In that way, the spectrometer 100 can be considered as beingminiaturized.

In one embodiment of the spectrometer 100, an angle 143, 144, 145 withan amount of between 10° and 120°, 10° and 110° or 10° and 100° liesbetween a first central ray of a beam of rays directed onto an opticalfunctional element 132 of the reflective imaging optics 130 or thedispersive optical element 120 and a second central ray of a beam ofrays radiated from the optical functional element 132 or the dispersiveoptical element 120. The central ray means, for example, a ray of a beamof rays lying on a symmetry axis of the beam of rays or havingapproximately the same distance to the outermost rays of the beam ofrays, i.e., is in the center of the beam of rays. This allowsminimization of the optical path volume and realization of thespectrometer with a small structural size.

In one embodiment of the spectrometer, the optical functional element132 is a mirror, a lens or a combination of the same, such as a Manginmirror. Thereby, electromagnetic radiation can be directed, collimatedand/or expanded by simple means. Since mirror and lenses can be producedin a manner suitable for mass production and in a cost-effective manner,the spectrometer can also be produced in large quantities at littlecost.

In one embodiment of the spectrometer, the optically effective area ofthe optical functional element 132 is a spherical, aspheric, toricaland/or biconical area and/or free from area consisting of an axial oroff-axial area portion, but an otherwise symmetrical area. Inparticular, spherical and cylindrical areas for the optical functionalelement 132 can be produced simply and cost effectively, for example byinjection molding or glass molding, whereby the spectrometer can beproduced cost effectively in large quantities.

In one embodiment of the spectrometer, the dispersive optical element120 comprises an electrostatic, piezoelectric or electromagnetic ormagnetostrictive drive for deflecting the dispersive optical element120. By the drive, it is possible to adjust the dispersive opticalelement 120 such that the electromagnetic radiation of differentwavelengths can be examined, since, depending on the angle of thedispersive element 120 relative to the optical functional element 132,beams of rays having differing wavelengths impinge on the outlet openingand/or detector area 150. An electrostatic, piezoelectric orelectromagnetic drive can be controlled in a very fine manner whereby itis possible to spectrally split light with a miniaturized spectrometerand to analyze the same with high accuracy.

In one embodiment of the spectrometer, the dispersive optical element120 comprises an optical or electric sensor for determining a deflectingposition of the dispersive optical element 120. By the sensor, thedeflection of the dispersive optical element 120 can, e.g., bedetermined exactly and thus the captured data can be analyzed veryaccurately with the miniaturized spectrometer.

In one embodiment of the spectrometer, the dispersive optical element120 is a diffraction grading and/or configured in a moveable and/orrotatable manner. Diffraction gratings can be produced in a mannersuitable for mass production and cost effectively and by a rotatableconfiguration electromagnetic radiation can be split variably.

According to an embodiment, the dispersive optical element 120 isconfigured in a static manner, wherein here, e.g., a scanning analysisas described in the context of FIG. 2b or no scanning analysis isperformed.

According to an embodiment, during non-scanning analysis, the fullspectrum is analyzed at the same time. Thus, for example, the fullspectrum leaves the outlet opening and can be captured by a linedetector or a planar detector. According to an embodiment, the staticdispersive element 120 is, e.g., a reflective optical element or atransmitting optical element.

In one embodiment, the diffraction grating (dispersive optical element120) is aberration corrected. This improves the spectral resolution ofthe spectrometer 100.

In one embodiment, the inlet opening 110, the outlet opening and/ordetector area 150, the at least one optical functional element 132 andthe dispersive optical element 120 are disposed directly or indirectlyon the carrier member 160. Here, for example, the inlet opening 110 andthe outlet opening and/or detector area 150 can be considered asindirectly disposed since the same are, for example, integrated directlyinto the carrier member. The reflective imaging optic 130 and thedispersive optical element 120 can, for example, be considered asindirectly disposed since the same are disposed, for example, asindividual members on the carrier member.

According to an embodiment, the members are adhered at least partly on aside of the carrier member facing away from the optical path volume,i.e. an outer wall, or mounted in a different manner, such that themember is applied directly to the carrier member or the outer wall oradjacent to the same. Here, the member can be placed such that theoptically effective element, such as the inlet opening 110, the outletopening and/or detector area 150, the at least one optical functionalelement 132 and/or the dispersive optical element 120 is facing theoptical path volume and is accessible for the optical path via at leastone lateral opening.

For providing an adjustment buffer zone for compensating productionvariations of the carrier member, the outer wall is configured in a flatmanner on the side, i.e. parallel to the extension of the outer wall,such that for placing the member before actually mounting the same, themember can be shifted transversally to the extension of the lateralopening.

FIG. 2a shows a schematic illustration of a spectrometer 100 having twooptical functional elements according to an embodiment of the presentinvention. The spectrometer 100 includes an inlet opening 110, adispersive optical element 120 and a reflective imaging optic 130 havingtwo optical functional elements 132 a and 132 b defining an optical path142 crossing from the inlet opening 110 across the dispersive opticalelement 120 onto an outlet opening 150 of the spectrometer. The twooptical functional elements 132 a and 132 b can have the same featuresand functionalities as the optical functional element 132 in FIG. 1.However, the first optical functional element 132 a does not have toshow the same features and functionalities as the second opticalfunctional element 132 b. In that way, for example, the first opticalfunctional element 132 a can have the function of a collimator and thesecond optical functional element 132 b can, for example, have thefunction of collimating a beam of rays. Further, the spectrometer 100comprises a carrier member 160 defining a flat optical path volume 140having four lateral openings. A first member corresponding to the inletopening 110 is disposed on a first opening, a second member into whichthe second optical functional element 132 b is integrated is disposed onthe second opening, a third member into which the first opticalfunctional element 132 a is integrated is disposed on a third openingand a fourth member into which the outlet opening 150 as well as thedispersive optical element 120 are integrated is disposed on the fourthopening.

In one embodiment of the spectrometer 100, the inlet opening 110 isconfigured to allow electromagnetic radiation to enter in an opticalpath 142 of the spectrometer 100 and to direct the same onto a firstoptical functional element 132 a of the reflective imaging optics 130.The first optical functional element 132 a is configured, for example,to collimate the electromagnetic radiation and to direct the same ontothe dispersive optical element 120. The dispersive optical element 120is configured, for example, to spectrally split the electromagneticradiation and to direct the same onto a second optical functionalelement 132 b of the reflective imaging optics 130, wherein theelectromagnetic radiation directed onto the second optical functionalelement 132 by the dispersive optical element 120 crosses theelectromagnetic radiation directed onto the first optical functionalelement 132 a from the inlet opening 110. The second optical functionalelement is configured, for example, to focus the electromagneticradiation within an optical depth of field and to direct the same ontothe outlet opening 150 and/or detector area, wherein the spectrallysplit electromagnetic radiation directed onto the outlet opening 150and/or detector area by the second optical functional element 132 bcrosses the electromagnetic radiation directed onto the first opticalfunctional element 132 a from the inlet opening 110 as well as theelectromagnetic radiation directed onto the dispersive optical elementby the first optical functional element 132 b. It is an advantage ofthis crossed optical path 142 that the spectrometer having a smalloptical path volume can be realized and can hence be produced with smallstructural size.

In one embodiment of the spectrometer 100, an angle 143 between a firstbeam of rays including electromagnetic radiation directed from the inletopening 110 onto a first optical functional element 132 a of thereflective imaging optics 130 and a second beam of rays includingelectromagnetic radiation directed onto the dispersive optical element120 by the first optical functional element 132 a is between 10° and100°. Thereby, the optical path volume is minimized wherebyspectrometers having small dimensions can be realized.

In one embodiment of the spectrometer 100, the outlet opening 150 or thedetector area and the dispersive optical element 120 are configuredmonolithically as a common member. Since several components areintegrated in one member, production of the spectrometer is simple andcost-effective since less members have to be produced and greaterprecision results since, as shown in FIG. 2a , two elements are producedexactly adjacent to one another in one member and do not have to bepositioned subsequently with high precision. Thus, a common member forseveral elements of the spectrometer is advantageous formass-production.

In other words, FIG. 2a shows a sectional view of a crossedCzerny-Turner monochromatic having the optical functional elements andthe carrier member for holding the components. The gap and the MEMSgrating are produced in silicon microtechnology. Additionally, theoutlet gap and the grating are integrated in a common chip. The carriermember comprises respective contact surfaces for precise placement andfixing of the optical members. These contact surfaces are disposed, forexample, on a lateral wall of the carrier member on a side facing awayfrom the optical path and at least part of the members is adhereddirectly on these contact surfaces.

According to an embodiment, FIG. 2b shows an inventive spectral analysissystem 100 which can also be referred to as spectroscopic apparatus. Thespectroscopic apparatus 100 can comprise features and functionalities ofthe spectroscopic apparatus of FIG. 1. The spectroscopic apparatus 100comprises an inlet opening 110 and an outlet opening and/or a detectorarea 150. Electromagnetic radiation 13 can enter through the inletopening 110 into an interior (optical path volume 140) of thespectroscopic apparatus 100. Additionally, the electromagnetic radiation13 can leave the outlet opening and/or detector area 150 from theinterior of the spectroscopic apparatus 100. When passing through therespective openings 110, 150, the electromagnetic radiation 13 can befiltered, wherein filtering the radiation 13 can take place, forexample, in the image plane, an aperture plane, a plane conjugated tothe same or between these planes. Here, the radiation 13 can be filteredlocally and/or spatially with respect to an object plane.

Further, the spectroscopic apparatus 100 comprises reflective imagingoptics 130 having at least one optical functional element 132, referredto, e.g. as first mirror below. The reflective imaging optics 130 can beconfigured to influence the radiation 13 in a beam-forming manner. Thefirst mirror can, for example, be a concave mirror. The first mirrorcan, for example, be a collimator mirror that is configured to collimatethe radiation 13. The first mirror can, for example, be arranged in afixed manner or can be configured in an unmovable manner.

Further, the spectroscopic apparatus 100 comprises a movable MEMS mirror15. The movable MEMS mirror 15 can be configured as micromechanicalmember and can have dimensions in the range of several millimeters. TheMEMS mirror 15 can be structured by means of microstructuring methods(e.g. lithography, etching technologies, etc.) into a suitablesubstrate. The MEMS mirror 15 comprises a rotating or tilting axis 16.The MEMS mirror 15 can be rotated or tilted around this rotation ortilting axis, which is indicated by means of the double arrow 17.

According to an embodiment, the spectral analysis system 100 comprisesan electrostatic, piezoelectric, electromagnetic or magnetostrictivedrive for deflecting the MEMS mirror 15.

According to an embodiment, the spectral analysis system 100 comprisesan optical or electric sensor for determining a deflection position ofthe MEMS mirror 15.

Electromagnetic radiation 13 can be reflected by the first mirror (theoptical functional element 132) and be guided to the movable MEMS mirror15, wherein the radiation 13 is at the same time influenced in abeam-forming manner by the first mirror. The radiation 13 influenced ina beam forming manner reaches the movable MEMS mirror 15 and can bereflected again there. According to the invention, the radiation isreflected by the MEMS mirror 15 to a dispersive optical element 120arranged in a spatially separate manner from the MEMS mirror 15. Thedispersive optical element 120 can, for example, be an opticaldiffraction grating, a prism or a photonic crystal.

The dispersive optical element 120 can be produced as element producedin microsystem technology, possibly even in combination but also bymolding methods or other replication technologies. The dispersiveoptical element 120 is arranged in a stationary manner or configured inan unmovable manner. Thus, the movable MEMS mirror 15 is movable inrelation to the dispersive optical element 120 arranged in a stationarymanner or, more accurately, rotatable or tiltable. Thus, FIG. 2b shows ascanning spectral analysis with an unmovable dispersive optical element120.

The dispersive optical element 120 is configured to spectrally split theradiation 13 influenced in a beam-forming manner by the first mirror andreflected by the movable MEMS mirror 15 into different orders ofdiffraction. Here, the dispersive optical element 120 has awavelength-selective effect, i.e. the incoming radiation 13 is splitinto different wavelengths, wherein radiation portions of a desiredwavelength or a desired wavelength range are selectively reflected at aspecific angle.

The portions of the radiation 13 split into a limited wavelength rangeby means of the dispersive optical element 120 are reflected back to themovable MEMS mirror 15 by the dispersive optical element 120. Thespectrally split radiation with the limited wavelength range is againreflected from the movable MEMS mirror 15 to the optical functionalelement 132.

Alternatively, instead of the individual optical functional element 132,two optical functional elements can exist as shown and described in FIG.2 a.

By means of the optical functional element 132, the spectrally splitradiation 13 with the limited wavelength range can be refocused onto theoutlet opening and/or detector area 150.

The exemplarily described arrangement of the individual elements withrespect to one another results in the shown optical path, wherein thepropagation direction of the electromagnetic radiation 13 along thisoptical path is indicated by arrows.

Here, it can be seen, among others, that the radiation reflected by themovable MEMS mirror 15 to the dispersive optical element 120 is split atexactly this dispersive optical element 120. One portion of theradiation 13 comprising a limited but desired wavelength range (e.g. afirst order maximum) is reflected back to the MEMS mirror 15. Otherportions of the radiation 13 whose wavelengths are outside the desiredwavelength range are filtered out. For example, such a portion of theradiation 13 is directed in a direction of the MEMS mirror 15 butbypassed laterally along the MEMS mirror 15. Another part of theradiation 13 can be guided, for example, to an inner wall of a carriermember 160 of the spectrometer which can serve, e.g., as radiationabsorption element in which the radiation 13 is absorbed at the innerwall. The radiation-absorbing inner wall of the carrier member 160 canbe arranged opposite to the main reflection area of the MEMS mirror 15.

All above-stated elements of the spectroscopic apparatus 100, i.e. themovable MEMS mirror 15, the inlet opening 110, the outlet opening and/ordetector area 150 and the dispersive optical element 120 have to becarefully aligned with respect to one another in spectroscopicapparatuses according to conventional technology, which is also referredto as alignment. For keeping the alignment effort as low as possible,according to the invention, the movable MEMS mirror 15 in the inventivespectroscopic apparatus 100 is configured with the inlet opening 110and/or the outlet opening and/or detector area 150 monolithically as afirst common member 1000. Optionally, the first common member 1000 canfurther comprise the fixed dispersive optical element 120, whereby, e.g.the lateral wall of the carrier member 160 between the MEMS mirror 15and the dispersive optical element 120 can be omitted.

Further, the carrier member 160 is produced of one mold, wherein onlylateral walls (shaded areas of the carrier member 160) are illustratedthat are connected via a bottom (not visible in FIG. 2b ). Thus, thecarrier member 160 comprises a substrate including a bottom and lateralwalls. Here, the bottom is arranged, e.g., parallel to an optical path142 and the lateral walls are arranged, e.g. perpendicular to theoptical path 142.

According to FIG. 2b , the carrier member 160 comprises three lateralopenings in the lateral walls where, e.g., one member can be fixed fromthe outside. Thus, the first common member 1000 can be disposed on oneof the three openings, the member 1100 including the reflective imagingoptics 130 with the first optical element 132 a can be arranged onanother opening and a third member including the fixed dispersiveoptical element 120 can be disposed on a further one of the threeopenings. Thus, the carrier member 160 already determines the positionsof the members, whereby a very exact spectroscopic apparatus can berealized in a miniaturized manner with a simple pick-and-place method.

According to an embodiment, it is possible that the movable MEMS mirror15 and the inlet opening 110 and/or the outlet opening and/or detectorarea 150 are configured in the same substrate which would correspond toan above-mentioned monolithic configuration. Alternatively oradditionally, it would be possible that the movable MEMS mirror 15 andthe dispersive optical element 120 are configured in the same substratewhich would also correspond to an above-mentioned monolithicconfiguration. The MEMS mirror 15 can be structured or configured, forexample, with the inlet opening 110 and/or the outlet opening and/ordetector area 150 and/or the dispersive optical element 120 on a commonchip.

The optical path 142 illustrated in FIG. 2b is, e.g., folded. Therefore,the spectrometer 100 can also be referred to as folded Czerny-Turnerspectrometer.

In contrary to that, FIG. 2c and FIG. 2d illustrate a crossed opticalpath 142 also with a fixed dispersive element 120. Thus, thespectrometer 100 in FIG. 2c and FIG. 2d can be referred to as crossedCzerny-Turner spectrometer.

The spectrometer 100 illustrated in FIG. 2c and FIG. 2d can comprisefeatures and functionalities of the spectrometer of FIG. 2b . Thespectrometer 100 in FIG. 2c and FIG. 2d comprises a first opticalfunctional element 132 a and a second optical functional element 132 b.The spectrometer 100 in FIG. 2c and FIG. 2d differs from thespectrometer 100 in FIG. 2b in that the radiation directed from thesecond optical functional element 132 b to the outlet opening and/ordetector 150 crosses the radiation directed from the inlet gap 110 ontothe first optical functional element 132 a.

The inlet opening 110 is configured, e.g., to allow electromagneticradiation to enter in an optical path 142 of the spectral analysissystem 100 and to direct the same onto the first optical functionalelement 132 a of the reflective imaging or beam-forming optics 130. Thefirst optical functional element 132 a is configured to collimate theelectromagnetic radiation and to direct the same onto the dispersiveoptical element 120, wherein the radiation can be directed via a movablemirror 15. The dispersive optical element 120 is configured tospectrally split the electromagnetic radiation and to direct the sameonto a second optical functional element 132 b of the reflective imagingor beam-forming optics 130, wherein the electromagnetic radiationdirected onto the second optical functional element 132 by thedispersive optical element 120 crosses the electromagnetic radiationdirected onto the first optical functional element 132 a from the inletopening 110 and can also be directed via the movable mirror 15.

The second optical functional element 132 b is configured, e.g., tofocus the electromagnetic radiation within an optical depth of field andto direct the same onto the outlet opening 150 and/or detector area. Thespectrally split electromagnetic radiation directed onto the outletopening 150 and/or detector area by the second optical functionalelement 132 b crosses the electromagnetic radiation directed onto thefirst optical functional element 132 a from the inlet opening 110 aswell as the electromagnetic radiation directed onto the dispersiveoptical element by the first optical functional element 132 b.

Depending on the arrangement of the individual components on a carriermember 160 of the spectrometer 100, different optical paths 142 can berealized. Here, according to an embodiment, devices such as the firstoptical functional element 132 a and/or the second optical functionalelement 132 b can be fixed to outer contact surfaces facing away fromthe optical path volume 140 (see, e.g., FIG. 2d ) or on lateral walls ofthe openings (see FIG. 2c ).

By means of the movable mirror 15, a scanning spectrometer 100 isrealized despite stationary dispersive element 120. Thus, large arraydetectors can be omitted. The movable mirror 15 can be produced in(silicon) micro or precision engineering technology and can hencerepresent an MEMS mirror.

FIG. 3 shows a schematic illustration of a dispersive optical element120 for the spectrometer according to an embodiment of the presentinvention. The dispersive optical element 120 is pivoted and realized asdiffraction grating. In other words, FIG. 3 shows a sectional view of anMEMS grating mirror produced in silicon microtechnology.

FIG. 4 shows a schematic representation of an MEMS gap 200 produced insilicon microtechnology for the spectrometer according to an embodimentof the present invention. The MEMS gap 200 can, for example, be used asinlet opening (such as the inlet opening 110 in FIG. 1 and FIG. 2a ) oras outlet opening (such as the outlet opening 150 in FIG. 1 and FIG. 2a).

FIG. 5 shows a schematic illustration of a gap 200 produced by means oflaser material processing in metal for the spectrometer according to anembodiment of the present invention.

In one embodiment, the inlet opening and/or the outlet opening isproduced by means of a laser material processing or a replicatingtechnology. Thereby, exact openings can be produced which increases theresolution capacity of the spectrometer.

FIG. 6 shows a schematic illustration of a member 300 of thespectrometer according to an embodiment of the present invention. Adetector area 150 a, an outlet opening 150 b and a dispersive opticalelement are integrated in the member 300. The outlet opening 150 b, thedetector area 150 a and the dispersive optical element 120 are disposed,for example, on a common wiring carrier 310, whereby the three elementscan be advantageously connected to one another and exactly positionedwith respect to one another. However, in one embodiment it is alsopossible that the outlet opening 150 b or the detector area 150 a anddispersive optical element 120 are disposed, for example, on a commonwiring carrier 310.

In one embodiment, the detector area 150 a detects the electromagneticradiation leaving the optical path 142 of the spectrometer through theoutlet opening 150 b in a spectrally split manner. By combining theoutlet gap with the detector area, beams of rays having a different wavelength than the wavelength to be analyzed can be easily sorted out.

In one embodiment, the detector area comprises an active area, whereinthe active area can act as outlet gap. In that case, the active areahas, for example, a rectangular shape of a suitable size which wouldmake a separate outlet gap obsolete. If, for example, no outlet gap butonly a detector area 150 a is used, the detector area 150 a has to bedesigned such that its expansion does not also detect beams of rayshaving a different wavelength than the one to be analyzed.

In other words, FIG. 6 shows a sectional view of an MEMS grating mirror(dispersive optical element 120) produced in silicon microtechnologyadjacent to an outlet gap 150 b produced by means of laser materialprocessing in metal. Both members are mounted on the same wiring carrier310. A detector (detector 150 a) results for detecting the spectrallysplit electromagnetic radiation coming out through the outlet gap 150 bis additionally placed in a cavity on the wiring carrier 310.

FIG. 7 shows a schematic illustration of a member 300 of thespectrometer into which both an outlet gap 150 b, a detector area 150 aas well as a dispersive element 120 are integrated according to anembodiment of the present invention. The outlet gap 150 b, the detectorarea 150 a as well as the dispersive element 120 are disposed on awiring carrier 310.

In other words, FIG. 7 shows a sectional view of an MEMS grating mirror(dispersive element 120) produced in silicon microtechnology where theoutlet gap 150 b is integrated in the same substrate 320. The MEMSmember 200 is mounted on the wiring carrier 310. A detector (detectorarea 150 a) for detecting the spectrally split electromagnetic radiation146 passing through the outlet gap 150 b is, for example, additionallyplaced on the wiring carrier 310.

FIG. 8 shows a schematic illustration of two members, a dispersiveoptical element 120 and an outlet gap 150 b forming a member 300 of thespectrometer with a wiring carrier 310 and a detector area 150 a andwhich are arranged on top of one another according to an embodiment ofthe present invention.

In other words, FIG. 8 shows, for example, a sectional view of an MEMSgrating mirror (dispersive optical element 120) produced in siliconmicrotechnology which is mounted on an MEMS outlet gap 150 b produced insilicon microtechnology. The member with outlet gap 150 b is mounted ona wiring carrier 310. A detector (detector area 150 a) for detecting thespectrally split electromagnetic radiation 146 passing through theoutlet gap 150 b, is, for example, additionally placed on the wiringcarrier 310.

FIG. 9 shows a schematic illustration of three members, a dispersiveoptical element 120, an outlet gap 150 b and a member 200 withintegrated detector area 150 a forming a member 300 of the spectrometertogether with a wiring carrier 310, wherein the three members arearranged on top of one another on the wiring carrier 310 according to anembodiment of the present invention.

In other words, FIG. 9 shows, for example, a sectional view of an MEMSgrating mirror (dispersive optical element 120) produced in siliconmicrotechnology which is mounted on an outlet gap 150 b produced bymeans of laser material processing in metal. The member with outlet gap150 b is mounted, for example, on the member 200 and the member 200 isdisposed, for example, on the wiring carrier 310. In one embodiment, thesubstrate 210 of the member 200 is monolithically connected to thewiring carrier 310 to one member “from one mold”. In this embodiment,for example, the member with outlet gap 150 b is mounted on the wiringcarrier 310 and a detector (detector area 150 a) for detecting thespectrally split electromagnetic radiation 146 passing through theoutlet gap 150 b is additionally placed in a cavity on the wiringcarrier 310.

The members 300 of FIG. 6, FIG. 7, FIG. 8 and FIG. 9 can have, forexample the same features and functionalities and can be mounted on acarrier member of a spectrometer described herein at one of the at leasttwo lateral openings, such that the optical path, projected along athickness direction of the optical path volume, comprises crossingoptical path portions.

FIG. 10 shows a schematic illustration of the spectrometer 100 withoutillustration of the carrier member according to an embodiment of thepresent invention. FIG. 10 shows the schematic view of a crossedCzerny-Turner monochromator, e.g., with the respective beams of raysfrom the inlet gap 110 across the optical functional elements to theoutlet gap 150. The spectrometer 100 comprises a dispersive opticalelement 120, a first optical reflective element 132 a and a secondoptical reflective element 132 b.

FIG. 11 shows a schematic illustration of the course of the optical pathof the spectrometer 100 according to an embodiment of the presentinvention. FIG. 11 shows the schematic view of a crossed Czerny-Turnermonochromator, for example with indicated main or central rays 148 ofthe beams of rays. The spectrometer 100 comprises an inlet gap 110, adispersive optical element 120, a first optical reflective element 132a, a second optical reflective element 132 and an outlet opening and/ordetector area 150.

In one embodiment, an angle 149 between a first central ray 148 a of abeam of rays passed through the inlet opening and a second central ray148 b of a beam of rays impinging on the outlet opening is between 10°and 120°. The angle 149 between the main rays of the optical pathportions between inlet gap and first mirror and second mirror and outletgap can also be in a range of 10° to 120°, 10° to 100° or 10° to 90°.Thus, the spectrometer 100 can be a Czerny-Turner MEMS spectrometer. Bythe specific structure, a miniaturized MEMS spectrometer 100 can berealized.

In one embodiment, all angles 143, 144, 145 and 149 illustrated in FIGS.1, 2 and 11 can also be in a range of 10° to 90°, 10° to 80°, 10° to 70°or 10° to 60°, such as at 45°.

In the following, further embodiments of the spectrometer are discussedwhere the optical path comprises a greater expansion into the thicknessdirection of the spectrometer compared to the above embodiments due tothe usage of deflection mirrors. By the deflection mirrors, the opticalpath can be placed in several planes.

FIG. 12 shows a schematic illustration of the spectrometer 100 includingthree deflection mirrors 400 a-400 c according to an embodiment of thepresent invention. FIG. 12 shows, for example, a crossed Czerny-Turnerspectrometer 100 in quasi planar structure. The spectrometer 100includes a carrier member including two parts, a bottom 312 and a lid314. The bottom 312 is, for example, formed as a tray with indentations315, 316 at the sides for pick and place assembly of reflective imagingoptics 130 with a first optical functional element 132 a and a secondoptical functional element 132 b from the top. The first opticalfunctional element 132 a and/or the second optical functional element132 b can be a mirror. The indentations 315, 316 form at least twolateral openings in the carrier member on which the at least twomembers, e.g., the first optical functional element 132 a and the secondoptical functional element 132 b, are mounted.

In one embodiment, the spectral analysis system 100 includes a lid. Inthe lid, at least one of the inlet opening, the outlet opening and/orthe detector area, the at least one optical functional element and thedispersive optical element is integrated. The lid 314 of thespectrometer 100 of FIG. 12 includes, e.g., an inlet opening 110, anoutlet opening 150 b, a detector area 150 a and a dispersive element120. Thereby, the spectrometer can be realized in a very small mannersince less elements of the spectrometer 100 increase or influence theexpansion perpendicular to the thickness direction 500.

In one embodiment, the deflection mirrors 400 a-400 c are configured todirect an optical path 142, e.g. in the direction of inlet and outletgap. In that way, the optical path 142 can impinge, e.g. from an inletgap 110 onto the deflection mirror 400 a, can be redirected from therein the direction of the first optical functional element 132 a and fromthere across the deflection mirror 400 b to a dispersive optical element120 from which the optical path impinges on a detector area 150 a acrossthe deflection mirror 400 b, the second optical functional element 132 band the deflection mirror 400 c through an outlet gap 150 b. Thedetector area 150 a can be formed, for example, as photodetector. Thedeflection mirrors 400 a-400 c can either be integrated as discretemembers for pick and place assembly into the bottom 312 from the top orcan be monolithically integrated in the bottom 312 and subsequentlymirrored.

In one embodiment, the optical path 142 runs mostly transversely to thethickness direction 500 and only part of the optical path runs parallelto the thickness direction 500. In that way, the optical path 142 inFIG. 12 travels, e.g. four short distances between elements disposed onthe lid 314 and the deflection mirrors 400 a-400 c on the bottom 312,parallel to the thickness direction 500 and four long distances betweenthe deflection mirrors 400 a-400 c and the first optical reflectiveelement 132 a or the second optical reflective element 132 b at an anglebetween 80° and 100° relative to the thickness direction 500. Thus, morethan 50% of the distance runs transversely to the thickness direction.However, it is also possible that more than 60%, 70% or even 75% of thedistance runs mostly transversely to the thickness direction 500.

In one embodiment, the bottom 312 or the lid 314 can include integratedstructures for suppressing stray light. The bottom 312 and/or the lid314 can be made, for example, of plastic or ceramics (possibly alsometal and composite materials). Metal material is particularlyadvantageous, since metal material screens the optical path volume fromoutside light. According to an embodiment, dyes can be added in plasticmaterials, or surface modifications, such as surface coating or surfaceroughening can be performed in order to screen outside radiation and/orto realize a stray radiation absorbing carrier member 160. Surfacemodifications can also be performed in a carrier member comprising metalmaterial for reducing stray radiation within the spectrometer. In oneembodiment, the lid 314 and/or the bottom 312 can be realized directlyas (stiffened) printed circuit board or can be configured as wiringcarrier. Basically, all common board technologies are possible for thebottom 312 and/or the lid 314, including 3D-MID technologies andceramics technologies (when folding the optical beam for the outlet gap150 b down to the bottom, the bottom 312 can also be produced in 3D MIDor ceramics technology.

In one embodiment, the optical functional elements (e.g., first opticalfunctional element 132 a and second optical functional element 132 b)can have different area shapes, e.g., spherical, aspherical,cylindrical, torical, biconical, generally asymmetrical (off-axis areaportions of different symmetrical or asymmetrical areas) and/or as amirror.

In one embodiment, gaps, e.g., the inlet gap 110 and the outlet gap 150b can be configured as separate members or can be integrated in the lid.The gaps can be produced of all accordingly machinable materials, suchas plastic, ceramic, metal, composite materials, silicon or similarmaterials known from semiconductor technology in a molding or ablativemanner. That way, the gap can be produced, for example by laserstructuring. Additionally, the gaps can be mounted, for example by pickand place possibly highly accurately in a planar manner on the bottomside of the lid 314 directed towards the direction of the bottom 312.

In one embodiment, the detector/detector area 150 a (photodiode or photoconductor etc.) can be mounted directly on the bottom side of the lid314 and can be contacted there if the lid 314 is configured as a wiringcarrier.

In one embodiment, electronic members 410, 412, 414 for spectrometerelectronics can be configured directly on the lid 314, either pointingto the outside or pointing to the inside or pointing both to the outsideand to the inside. An advantageous space gain can be obtained withelectronic members 410, 412, 414 directed to the inside. The electronicmembers 410, 412, 414 can be service mounted devices (smd) regulating,for example, a deflection of the dispersive optical element 110 orcontrolling the detector area 150 a.

In one embodiment, an MEMS, e.g., the dispersive optical element 120,has similar features as the detector 150 a, e.g., assembly on the bottomside of the lid if a third deflection mirror 400 b exists in the opticalpath 142. Advantages of this variation are, among others, thatproduction of the essential optical members (e.g., the opticalfunctional elements 132 a and 132 b) is possible by means of injectionmolding (suitable for mass production), that a greatly simplifiedassembly with standard planar pick and place technology can be used inthat only a final assembly step is needed when joining lid 314 andbottom 312, and that the inlet gap 110 and the board (e.g., the lid 314)are favorably situated for usage in mobile terminal devices.

In one embodiment, the outlet gap 150 b can be omitted due to an adapteddesign of the active detector area 150 a, the same acts, for example,simultaneously as exit gap 150 b with mostly rectangular shape, whichrepresents, e.g., a simplification of the spectrometer 100 illustratedin FIG. 12. A further simplification of the spectrometer could berealized by integrating the inlet gap 110 in the lid 314 (or bottom 312)which realizes minimization of the number of devices.

Even when the bottom 312 and the lid 314 are illustrated in a spatiallyseparate manner in the schematic illustration of the spectrometer 100 inFIG. 12, the bottom 312 and the lid 314 are connected to one another.Further, the bottom 312 as well as the lid 314 can also have, instead ofa hexagonal base as shown in FIG. 12, more or less corners or lateralsurfaces or can have round lateral surfaces or even wave-shaped lateralsurfaces.

In the following FIGS. 13 to 16, enlargements among others of the bottom312 and the lid 314 of the spectrometer 100 of FIG. 12 are shown fromdifferent perspectives. All elements having the same reference numbersas the elements in FIG. 12 can have the same features andfunctionalities as the corresponding elements in FIG. 12.

FIG. 13 shows a schematic illustration of the bottom 312 of thespectrometer 100 of FIG. 12 with the same elements as in FIG. 12according to an embodiment of the present invention.

FIG. 14 shows a schematic illustration of an area of the lid 314 of thespectrometer 100 of FIG. 12 pointing in the direction of the bottom 312with the same elements as in FIG. 12 according to the embodiment of thepresent invention.

FIG. 15 shows a schematic illustration of an area of the lid 314 of thespectrometer 100 of FIG. 12 pointing in the direction of the bottom 312without the inlet gap 110 and without the outlet gap 150 b according toan embodiment of the present invention. A first cavity 111 and a secondrecess 151 are integrated in the lid 314. The first cavity 111 islimited by the inlet gap 110 and the second cavity with the outlet gap150 b in the direction of the bottom of the spectrometer 100 of FIG. 12.The detector area 150 a is integrated in the second cavity 151.

FIG. 16 shows a schematic illustration of an area of the lid 314 of thespectrometer 100 of FIG. 12 pointing in the direction of the bottom 312with the deflection mirrors 400 a-400 c according to an embodiment ofthe present invention. The deflection mirrors 400 a-400 c as well as thefirst optical functional element 132 a and the second optical functionalelement 132 b are arranged on a bottom 312 of the spectrometer 100 asshown in FIG. 12, which is not shown in FIG. 16.

Even when a crossed optical path 142 is illustrated in the FIGS. 12 to16, the spectrometer 100 can also be realized with a non-crossed opticalpath.

FIG. 17 shows a schematic illustration of the spectrometer 100 includingtwo deflection mirrors 400 a and 400 c according to an embodiment of thepresent invention.

In one embodiment, the spectrometer 100 includes at least one deflectionmirror 140 a, 140 c.

FIG. 17 shows a slightly amended variation of the spectrometer 100 ofFIG. 12. An additional board/substrate 318 is arranged, for example, ata lateral surface for receiving the dispersive optical element 120(MEMS). This means that, for example, the dispersive optical element 120is arranged on a surface of the substrate 318 pointing to the opticalpath volume 140. Therefore, e.g., no third folding mirror, e.g. thedeflection mirror 400 b of FIG. 12, is needed, which results in lesstolerance issues. But one side wall of the bottom 312 includes, forexample, a third indentation 317.

In one embodiment, the substrate 318 includes electronic members 416,418 which can have the same features and functionalities as theelectronic members 410, 412 and 414 of FIG. 12.

In one embodiment, the lid 314 of the spectrometer 100 comprises a flexconnection 420 to the lateral board (substrate 318) with MEMS. Thus,during final assembly, the substrate 318 can be folded down and thedispersive optical element 120 is inserted into the third indentation317. For example, a flex board can be used for the lid 314 with thesubstrate 318.

In one embodiment, the spectrometer 100 of FIGS. 1, 2, 10, 11, 12 and 17can include a temperature sensor for measuring the temperature at or inthe spectrometer 100, which is a supplement.

In the following FIGS. 18 to 20, enlargements, among others of thebottom 312 and the lid 314 of the spectrometer 100 of FIG. 17, areillustrated from different perspectives. All elements having the samereference numbers as elements in FIG. 17 can have the same features andfunctionalities as the corresponding elements in FIG. 17.

FIG. 18 shows a schematic illustration of the bottom 312 of thespectrometer 100 of FIG. 17 having the same elements as in FIG. 17according to an embodiment of the present invention. Additionally, apossible crossed optical path 142 is shown.

FIG. 19 shows a schematic illustration of an area of the lid 314 of thespectrometer 100 of FIG. 17 pointing in the direction of the bottom 312with a substrate 318 according to an embodiment of the presentinvention.

FIG. 20 shows a schematic illustration of an area of the lid 314 of thespectrometer 100 of FIG. 17 pointing in the direction of the bottom 312with a substrate 318 and two deflection mirrors 400 a and 400 caccording to an embodiment of the present invention. Additionally, apossible crossed optical path 142 is shown. The two deflection mirrors400 a and 400 c as well as the first optical functional element 132 aand the second optical functional element 132 b are disposed on thebottom 312 of the spectrometer 100 as shown in FIG. 17, which is notshown in FIG. 20.

FIG. 21 shows a schematic illustration of the spectrometer 100 havingonly one optical functional element 132 according to an embodiment ofthe present invention. This is, for example, a crossed Monk-Gilliesonspectrometer. The difference to a Czerny-Turner spectrometer is, e.g.that the spectrometer 100 includes only an imaging mirror (opticalfunctional element 132) and a grating (dispersive optical element 120)in the convergent or divergent optical path 142, wherein no collimationof the electromagnetic radiation is performed as in a Czerny-Turnerspectrometer. Apart from that, the spectrometer 100 comprises almost allfeatures of the Czerny-Turner spectrometer (see FIGS. 1, 2, 10, 11, 12and 17). Thus, the spectrometer 100 comprises, e.g., an inlet gap 110,an outlet gap and/or a detector area 150, reflecting optics 130 havingan optical functional element 132 and a dispersive optical element 120which is rotatable. In FIG. 21, the carrier member connecting theindividual elements of the spectrometer 100 is not shown. The opticalfunctional element 132 is, for example, a concave mirror.

One particularity in this variation of the spectrometer 100 is thediffraction grating 120. Advantageously, the grating is configured in anaberration-corrected manner, i.e., a specific variation of the linedistance and/or a deviation from a straight line is caused forincreasing the spectral resolution.

In one embodiment, the dispersive optical element 120 is in a convergentor divergent part of the optical path 142. In this case, the dispersiveoptical element 120 can have, e.g., several functions, on the one hand,e.g. spectrally splitting the incoming electromagnetic radiation and, onthe other hand, directing and focusing the spectrally split radiation inthe direction of the outlet gap and/or the detector area 150. Thereby,fewer members are needed for the spectrometer 100 which results a morecost-effective production.

FIG. 22 shows a schematic illustration of the spectrometer 100 of FIG.21 having only one optical functional element 132 and no crossed opticalpath 142 according to an embodiment of the present invention. Since theoptical path 142 is not crossed, the spectrometer can be produced inlarge quantities and at little cost by the specific design with thecarrier member not shown in FIG. 22. Additionally, the spectrometer 100can be realized to be small, but not as greatly miniaturized as in acrossed optical path. A further difference to the spectrometer 100 ofFIG. 21 is that the spectrometer 100 of FIG. 22 comprises both an outletgap 150 b as well as a detector area 150 a.

In other words, the invention is based on the finding that miniaturizedspectroscopic apparatuses with quite good performance can be producedwith the MEMS devices described in conventional technology, but that thesame have, in the known embodiments, a serious drawback standing in theway of economical production. The embodiments described in conventionaltechnology are stacked structures, i.e. the spectroscopic apparatus iscomposed of a stack of different substrates or sub-assemblies. Thisbasic structure allows basically the cost-effective production of agreatly miniaturized spectrometer in large quantities with the method ofmodern microassembly. However, a basic prerequisite is a cost-effectiveavailability of all members in the substrate stack. However, this iscurrently not the case. Due to the geometry of the included opticalpath, the stacked approach needs a complexly shaped member havingseveral mirror areas. For ensuring the device function, this member issubject to tight tolerances. Due to this fact, the production istechnically expensive and cannot be produced with production processessuch as injection molding or glass molding that are suitable formass-production.

The inventive solution avoids such complicated members and hence allowseconomical production with the same performance. For this, theapproaches and geometries of the optical path used so far are deviatedfrom and instead a design referred to as crossed Czerny-Turner assemblyis used. The same is basically known but it is novel in miniaturizedform in combination with movable MEMS diffraction gratings. Thereby, thecomplex two mirror member is “disintegrated” into two, e.g. simplerotationally symmetrical mirrors. The same can be produced, e.g., withcurrently available technologies without any problems with high accuracyand in different quantities, from small batches up to enormousquantities. This is possible due to the significantly simplified design(rotational symmetry) of the optical functional elements. By crossingthe respective parts of the optical path, additionally, largerseparation of the two mirror areas as an example for an opticalfunctional element results, such that, e.g., the room needed forprocess-safe assembly results. A further advantage of the crossedoptical path compared to conventional technology for stacked MEMSspectrometers is a significantly greater distance of inlet and outletgaps, since the same are now, e.g., on different sides of thespectroscopic apparatus. Thereby, the integration of a frequentlyoptionally needed coupling-in optics in front of the inlet gap isgreatly simplified.

The needed MEMS grating mirrors can be taken, for example, fromconventional technology. However, the invention includes a number ofembodiments for which also new adapted MEMS members are used. Forexample, the outlet gap can be integrated in an MEMS substrate and hencethe assembly effort can be reduced and some tolerances can be selectedto be very tight, which is again favorable for system performance.

A further important feature of the invention is the option of mountingall functional elements (e.g. inlet gap, outlet gap, reflective imagingoptics, dispersive optical element) directly on a carrier member.Normally, for the assembly of compact spectrometers, significantly moremechanical parts for holding the optical function elements are neededdue to the structural size. Compared to the stacked MEMS spectrometers,e.g. when using only one member for holding (e.g. the carrier member),no chains of tolerance for the position of the optical functionalelement built up. Due to, for example the small structural size of theinventive solution, very different methods can be used for producing thecarrier member which again reach from the small batch to bulkproduction. As examples, machining, additive productions methods andinjection molding are stated.

Advantages in systems engineering for automated microassembly (“pick andplace” technology) nowadays allow very efficient assembly of theinventive solution even when the purely stacked process is departed fromin favor of a multi-facet approach. A further advantage of this approachis, e.g., an enormous mechanical and thermal stability gain of theoverall system.

Additionally, in the spectrometer described herein, for example, bendingsubstrates can be used and the folding assembly can be used as method.

The spectrometer described herein can be described, in other words, bythe following embodiments.

In one embodiment, the spectroscopic apparatus/spectrometer forperforming spectral analytical measurement comprises the followingelements:

-   -   an inlet opening through which the electromagnetic radiation can        enter an optical path of the spectroscopic apparatus;    -   a first optical functional element for collimation of the        radiation;    -   a dispersive optical element for spectral splitting of        electromagnetic radiation;    -   a second optical functional element for focusing the radiation;    -   an outlet opening through which the spectrally split        electromagnetic radiation can leave the optical path;        wherein the elements are arranged such that an optical path is        formed where the radiation passing through the inlet opening        impinges on the first optical functional element in the form of        a beam of rays, then onto the dispersive optical element, then        onto the second optical functional element and can then leave        the optical path through the outlet opening        and wherein the part of the beam of rays passing between the        inlet opening and the first optical element and the part of the        beam of rays passing between the second optical element and the        outlet opening cross each other.

In one embodiment, the first optical functional element includes amirror or a lens.

In one embodiment, the second optical functional element includes amirror or a lens.

In one embodiment, the optically effective areas of the opticalfunctional elements include spherical or aspherical or cylindrical orbiconical areas.

In one embodiment, an angle between a main ray or central ray of thefirst beam of rays and a main ray or a central ray of the second beam ofrays is between 10° and 100°.

In one embodiment, the dispersive optical element is configured in arotatable manner.

In one embodiment, the dispersive optical element includes a diffractiongrating or the dispersive optical element is a diffraction grating.

In one embodiment, the diffraction grating is configured as rotatablemicromechanical device.

In one embodiment, the micromechanical device is produced in siliconmicrotechnology.

In one embodiment, the micromechanical device comprises an electrostaticor piezoelectric or electromagnetic drive for deflecting the diffractiongrating.

In one embodiment, the micromechanical device comprises an optical orelectric sensor for determining a deflection position of the device.

In one embodiment, the inlet opening and/or the outlet opening isproduced in a silicon microtechnology or by means of laser materialprocessing.

In one embodiment, the rotatable diffraction grating and the outletopening are produced in a common substrate.

In one embodiment, the inlet opening, the outlet opening, the twooptical functional elements and the dispersive optical element aremounted on a common mechanical carrier substrate or carrier member.

In one embodiment, a detector/detector area for detectingelectromagnetic radiation is arranged in beam direction behind theoutlet opening.

In one embodiment, the micromechanical device and the detector fordetecting electromagnetic radiation are arranged on a common wiringcarrier.

In one embodiment, the micromechanical device and the outlet opening areproduced in a common substrate and the same is arranged on a commonwiring carrier with a detector/detector area for detectingelectromagnetic radiation.

In one embodiment, the focal length range of the at least one opticalfunctional element of the optically reflective imaging optics is in arange having a bottom limit of 100 mm, 150 mm, 200 mm, 250 mm, 300 mm or350 mm and an upper limit of 550 mm, 600 mm, 700 mm, 800 mm or 1000 mm.

In one embodiment, a monolithic bending substrate is used for thecarrier member.

While this invention has been described in terms of several advantageousembodiments, there are alterations, permutations, and equivalents whichfall within the scope of this invention. It should also be noted thatthere are many alternative ways of implementing the methods andcompositions of the present invention. It is therefore intended that thefollowing appended claims be interpreted as including all suchalterations, permutations, and equivalents as fall within the truespirit and scope of the present invention.

1. Spectral analysis system for capturing a spectrum, comprising aninlet opening, a dispersive optical element and an at least partlyreflective imaging or beam forming optics comprising at least oneoptical functional element defining an optical path from the inletopening across the dispersive optical element onto an outlet openingand/or detector area of the spectral analysis system, wherein thedispersive optical element is configured in a stationary manner; and acarrier member defining a flat optical path volume comprising at leastone lateral opening, wherein at least one of the inlet opening, theoutlet opening and/or detector area, the at least one optical functionalelement and the dispersive optical element is integrated in at least onemember, wherein the at least one member is mounted on the carrier memberat the at least one lateral opening, such that the optical path mainlyruns transversely to a thickness direction of the optical path volume.2. Spectral analysis system according to claim 1, wherein the carriermember defines a flat optical path volume comprising at least twolateral openings and/or wherein the at least two lateral openings are atan angle to each other.
 3. Spectral analysis system according to claim1, wherein the at least one member is disposed on a side of the carriermember facing away from the optical path volume.
 4. Spectral analysissystem according to claim 1, wherein the carrier member comprises abottom and lateral walls and wherein the at least one lateral opening isdisposed in at least one of the lateral walls.
 5. Spectral analysissystem according to claim 1, wherein the optical path is a crossedoptical path comprising crossing optical path portions projected alongthe thickness direction of the optical path volume.
 6. Spectral analysissystem according to claim 1, wherein the inlet opening is configured toallow electromagnetic radiation to enter an optical path of the spectralanalysis system and to direct the same onto a first optical functionalelement of the reflective imaging or beamforming optics; wherein thefirst optical functional element is configured to collimate theelectromagnetic radiation and to direct the same onto the dispersiveoptical element; wherein the dispersive optical element is configured tospectrally split the electromagnetic radiation and to direct the sameonto a second optical functional element of the reflective imaging orbeamforming optics, wherein the electromagnetic radiation directed bythe dispersive optical element onto the second optical functionalelement crosses the electromagnetic radiation directed from the inletopening onto the first optical functional element; wherein the secondoptical functional element is configured to focus the electromagneticradiation within an optical depth of field and to direct the same ontothe outlet opening and/or detector area, wherein the spectrally splitelectromagnetic radiation directed by the second optical functionalelement onto the outlet opening and/or detector area crosses both theelectromagnetic radiation directed from the inlet opening onto the firstoptical functional element as well as the electromagnetic radiationdirected by the first optical functional element onto the dispersiveoptical element.
 7. Spectral analysis system according to claim 1,wherein the dispersive optical element is within a convergent ordivergent part of the optical path.
 8. Spectral analysis systemaccording to claim 1, wherein an angle between a first central ray of abeam of rays directed onto an optical functional element of thereflective imaging or beamforming optics or the dispersive opticalelement and a second central ray of a beam of rays reflected by theoptical functional element or dispersive optical element is between 10°and 120° and/or wherein an angle between a first central ray of a beamof rays passing through the inlet opening and a second central ray of abeam of rays impinging on the outlet opening is between 10° and 120°. 9.Spectral analysis system according to claim 1, wherein the spectralanalysis system comprises a lid, wherein at least one of the inletopening, the outlet opening and/or the detector area, the at least oneoptical functional element and the dispersive optical element isintegrated in the lid.
 10. Spectral analysis system according to claim1, wherein the optical path mostly runs transversely to the thicknessdirection and only part of the optical path runs parallel to thethickness direction.
 11. Spectral analysis system according to claim 1,wherein the inlet opening, the outlet opening and/or detector area, theat least one optical functional element and the dispersive opticalelement are disposed directly or indirectly on the carrier member. 12.Spectral analysis system according to claim 1, wherein the at least oneoptical functional element comprises a mirror, a lens or a combinationof the same; and/or wherein the optically effective area of the at leastone optical functional element is a spherical, aspherical, cylindrical,torical and/or biconical area and/or freeform area.
 13. Spectralanalysis system according to claim 1, wherein the dispersive opticalelement comprises a movable mirror; and/or wherein the spectral analysissystem comprises an electrostatic, piezoelectric, electromagnetic ormagnetostrictive drive for deflecting the dispersive optical element;and/or wherein the spectral analysis system comprises an optical orelectric sensor for determining a deflecting position of the mirror. 14.Spectral analysis system according to claim 1, wherein the dispersiveoptical element comprises a diffraction grating and/or the grating isaberration-corrected.
 15. Spectral analysis system according to claim 1,wherein the detector area comprises an active area, wherein the activearea acts as outlet gap and/or wherein the outlet opening or thedetector area and the dispersive optical element are arranged on acommon wiring carrier.
 16. Spectral analysis system according to claim1, wherein the inlet opening and the outlet opening are integrated in acommon member or are arranged on the same.
 17. Spectral analysis systemaccording to claim 1, wherein the detector area detects theelectromagnetic radiation leaving the optical path through the outletopening in a spectrally split manner.
 18. Spectral analysis systemaccording to claim 17, wherein the outlet opening is arranged on acommon wiring carrier with the detector area and the dispersive opticalelement.
 19. Spectral analysis system according to claim 1, wherein theinlet opening, the outlet opening and/or the dispersive optical elementare produced in silicon microtechnology and/or wherein the inlet openingand/or the outlet opening are produced by means of laser materialmachining or a replicating technology.
 20. Spectral analysis systemaccording to claim 1, wherein the spectral analysis system is of thetype of a Czerny-Turner or a Monk-Gillieson spectrometer.
 21. Method forcapturing a spectrum by means of a spectral analysis system according toclaim 1.